A cabin generally refers to a room on a ship. The main hull is usually the part below the upper deck, and its interior is composed of staggered bulkheads, which divide the main hull into independent compartments. These cabins include engine room, ballast tank, oil tank, fresh water tank, isolation tank, anchor chain tank, waterproof tank, cargo tank and so on. Cargo hold can be divided into bulk cargo hold and liquid cargo hold. These cabins have their own special purposes, and they provide guarantee for the navigation of ships.